1. Field of the Invention
The present invention relates to bulked continuous filament (BCF) bundled yarns, and, more particularly, to bulked continuous filament bundled yarns made from differently colored singles yarns wherein the bundled yarns are capable of providing space-dyed effects in tufted floor coverings.
2. Description of Related Art
As used herein, certain terms have the meanings ascribed to them as follows:
The terms "thread" and "filament" are intended to connote single filament fibers, whereas "singles yarn" or "strand" is an assembly of two or more threads or filaments.
The term "node" is intended to mean relatively compact, tangled sections of a yarn that are separated by relatively bulky or unentangled sections.
The term "entangling" is intended to mean the mixing of fiber components to an extent that the individual components cohere to one another, where "cohere" means to stick or hold together in a visually identifiable and distinguishable mass, an example of which is the above-mentioned "node". Entangling includes directing a flow of fluid, such as air, against a moving plurality of strands transversely of the direction of movement of the strands. The resulting dislocation of the strands leads to a knot-like intertwining and entangling of the strands. The term "air-jet entangler" is a device which achieves an entangled yarn by co-mingling the components of the yarn.
A "texturing process" causes a permanent departure from the original longitudinal shape of the filament, for example, by causing the filament to be crimped, or to have some degree of curved or angular change along its length. One example of a texturing process employs a chamber in which a yarn is moved at high speed through a flow of heated gas or vapor, i.e., hot air or steam. Alternatively, heated or unheated yarn may be moved at high speed through a mechanical crimping process. In either arrangement, the fiber is then bulked by collision with a surface which, for practical purposes, may be the wad or plug formed by the yarn itself. As a consequence, individual yarns deposit themselves in a regularly bent configuration on an impact surface, and because of heat-induced effects, the yarns to some degree retain this curved or angular configuration. In the embodiment in which the fiber is heated with air, the crimped fiber configuration is made permanent by a cooling process, without permitting portions of the yarn to adhere, or be connected, to each other.
Singles yarns may be combined into plied yarns in several ways that usually involve the use of texturing of filaments followed by air-jet entangling. For example, three separate singles yarns can be combined into a final BCF product. The process may be a "one-step" or "two-step" process. The one-step process begins with forming the spun filaments making up the yarns and continues through all subsequent steps to winding of the final product, without interim spooling. In known two-step processes, the spun yarns are wound up after the first step of spinning, drawing, and texturing. The second step typically involves unwinding the yarn from a storage spool, which includes precision tension control before commencing the entangling step.
Both the one-step and two-step processes often employ a number of known steps, however, various permutations of those steps, together with uniquely selected parameter settings, determine which of a wide variety of results are achieved, in terms of filament and yarn configuration, and/or in terms of the appearance and performance of the ultimate product produced using such yarns. A specific sequence of process steps, along with a corresponding selection of process parameters, such as temperature, yarn tension, and other particulars, can determine a unique and possibly unforeseeable result, in terms of yarn specifications and functional and appearance qualities of a carpet made from the yarn.
One particular BCF yarn product is a space-dyed yarn, which has repeated, random or regular, intense bands of different colors along its length, which provide unique accent styling, primarily, but not exclusively, in tufted floor coverings, such as carpets. Such carpet products are normally manufactured by post-coloring of uncolored spun yarns with dyestuffs in an intermittent, regular or random, fashion. The yarns are then (ply)twisted and heat set. An example of such methods may be found in U.S. Pat. No. 4,153,961. Such yarns, when fully processed into carpet face yarns, exhibit pinpoints or larger "pixels" of different colors against a more mixed background shading. Depending on the regularity of spacing between colors, and the length of the different colors present in the yarns, the carpet can also feature a wider repeat patterning of areas of single perceived shade and areas of pinpoints of bright colors against a background of the single perceived shade.
Such effects are, to a large extent, different from those achieved with socalled "heather" yarns. Heather yarns, while also containing different colors, are mixed in such a way during processing that no one color predominates, and a single shade is perceived in carpeting made from such yarns, except on very close inspection. A heather appearance includes small points of individual color, i.e., color points, randomly distributed throughout a matrix of contrasting colors. In contrast to processes for making space-dyed yarn products, processes for making heather yarns are formulated to prevent the formation of any directional carpet appearance or patterns, such as streaks and chevrons in the finished product.
In order to eliminate the complex dyeing processes used to manufacture "true" space-dyed yarns, attempts have been made to utilize yarns which have been pre-colored in single colors, either by dyeing or by melt pigmentation. Such pre-colored singles yarns have been combined, in groups of two or more, with at least one group being of a different color than the others, to provide final yarns with a variety of coloring effects. The specific sequence of the process steps is as important as the selected steps, themselves. Such yarn products are referred to as "apparent space-dyed yarns" as their effects in a tufted product make them appear to be space-dyed yarns.
U.S. Pat. No. 5,804,115 discloses a one-step process for producing an apparent space-dyed yarn, made by sequentially spinning two or more strands having two or more colors, forming two or more yarn fractions from the strands, independently texturing and entangling at least one of the yarn fractions, and then together entangling all of the yarn fractions. This arrangement suffers from restrictions on process control flexibility, because it is performed as a one-step process. In a one-step process, fibers are spun at a minimum viable rate, e.g., 500 m/min., which, at a conventional 3:1 draw ratio, results in a downstream feed rate of 1500 m/min. At this rate, a desired level of precision in the downstream processing, in particular, in the air-jet entangling, cannot be attained. As a result, the space-dye effect of the yarn product when tufted into carpet is not as pronounced or as crisp as it otherwise might be.
The above process and products are, to varying degrees, unsatisfactory in terms of complexity, and/or their inability to provide the range of effects required to simulate true space-dyed yarns. Thus, there remains a need for a process for producing a simple, effective, product yarn series which can match all of the effects possible using true space-dyed yarns, and to produce other unique effects not possible by other means.